Mechanism of ultrasonic flotation column in enhancing flotation of fine grained phosphate ore resources

Despite the successful application of ultrasonic flotation column at the laboratory scale, its enhancement mechanism remains to be elucidated. Taking phosphorus-bearing iron tailings as the research object, this study compared the flotation performances of a mechanical flotation cell, a conventional flotation column, and an ultrasonic flotation column. By integrating high-speed photography, laser particle size analysis, scanning electron microscope with energy dispersive spectroscopy (SEM-EDS), contact angle measurements, total organic carbon (TOC) analysis, and collision probability calculations, the effects of ultrasound on bubble characteristics, particle dispersion, surface properties, and bubble–particle interactions were systematically investigated. The flotation results demonstrate that both the ultrasonic and conventional flotation columns achieved superior P 2 O 5 concentrate grades and separation efficiencies compared to the mechanical flotation cell, with the ultrasonic flotation column yielding a more significant improvement in concentrate grade. Mechanistic analysis reveals that ultrasound effectively refines bubbles, disperses particle aggregates, cleans mineral surfaces, and enhances the exposure of phosphorus and calcium elements. Consequently, this optimizes the action environment for flotation reagents and increases the attachment probability between fine mineral particles and bubbles. The coupled synergistic effect of these two mechanisms effectively improves the flotation efficiency of fine grained phosphate minerals.